[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-ppc] [PATCH 5/5] pseries: Move XICS initialization before cpu

From: Alexander Graf
Subject: Re: [Qemu-ppc] [PATCH 5/5] pseries: Move XICS initialization before cpu initialization
Date: Sat, 16 Mar 2013 07:07:30 +0100

Am 16.03.2013 um 06:41 schrieb Benjamin Herrenschmidt <address@hidden>:

> On Sat, 2013-03-16 at 06:33 +0100, Alexander Graf wrote:
>>>> We're changing that notion in the in-kernel XICS discussions.  The
>> flow will look like this:
>>>> * create vcpus
>>>> * create XICS
>>>> * foreach (vcpu)
>>>>     * enable_cap(vcpu, CAP_XICS_SERVER, xics_handle)
>>> This is stupid. Why have the VCPU initialize itself for non-kernel
>>> interrupts and *then* switch it over ?
>> Because non-kernel initialization is a nop.
> And ?

Compared to the previous aproach of a vm wide irq type, we win:

  - less vm global state
  - possibility of defining the 'cpu nr' from the pic's point of view
  - the same mechanism and code paths for hotplug and non-hotplug
  - possibility of supporting multiple pics
  - less implicit assumptions

While the code changes required to make this work should be minimal over the 
"set irq architecture" approach. It really makes life easier for everyone.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]